Evidence of earthquakes triggered by the tidal force of the sun and the moon——On the temporal characteristics of the earthquakes in Xingtai,Hejian and Tangshan

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Geology of the Grove Mountains in East Antarctica——New evidence for the final suture of Gondwana Land

As the core block of the East Gondwana Land, the East Antarctic Shield was traditionally thought, before 1992, as an amalgamation of a number of Archaean-Paleoproterozoic nuclei, be-ing welded by Grenville aged mobile belts during 1400—900 Ma, while the …     

Numerical Study on the Effect of the Manila Seismic Tsunami on the Guangdong Coast——The Nonlinear Effects of Tides and Tsunamis

The coupling numerical model between astronomical tide and tsunamis was built based on the data of the COMCOT model, which was verified by the Japan "3·11" tsunami. The tsunami source of the Manila seismic tsunami was designed and computed to analyze the risk of tsunami which will happen in the Guangdong coast. According to the results, the maximum quantity of water increasing and the time of the tsunami arriving at the Guangdong seacoast were calculated. The coupling simulation between astronomical tide and tsunamis has significant meaning for evaluating the risk and early-warning of tsunamis in the Guangdong coastal area.     

Simulation analysis on the regulation of overflow ecological water consumption in arid areas——A case study in the Canmrik ecological area of the mainstream zone of the Tarim River

After analyzing the regulation of overflow ecological water consumption in the Canmrik ecological area of mainstream zone of the Tarim River, in this paper a model of ecological bifurcation is developed, the dynamic overflow process of ecological bifurcation is simulated, and the quantitative relationships between the volume of ecological water consumption and the ecological conservation extent and overflow time are analyzed using GIS, advance of freshet and RS means. The results reveal that the effects of discharge and time of ecological bifurcation on the efficiency of ecological water consump-tion are significant, there is a geometrical exponential relationship between the efficiency of ecological bifurcation and the water supply with different discharges and different times under the same eco-logical water consumption, hypsography plays an important role in ecological water consumption, the regulation of ecological water consumption cannot be equated with the ordinary farming irrigation system, a serious water waste will result and the prospective ecological benefits will not be able to be achieved if an ordinary ecological bifurcation is implemented. The efficiency of ecological water con-sumption can be increased by 30% by selecting the bifurcation schemes in an optimized way, which is of the utmost importance for arid areas with shortage of water resources.     

The P-wave velocity structure of the lithosphere of the North China Craton——Results from the Wendeng-Alxa Left Banner deep seismic sounding profile

For the first time on the Chinese mainland, long-range wide-angle seismic reflection/refraction profiling technology has been applied to seismic wave phases from different depths and with different attributes within the various blocks of the North China Craton to characterize the structure of the crust and upper mantle lithosphere. By comparative analysis of the seismic wave phase characteristics in each block across a 1500-km-long east-west profile, we have identified conventional Pg, Pci, PmP and Pn phases in the crust, made a clear contrast between PL1 and PL2 waves belonging to two groups of lithospheric-scale phases, and produced a model of crust-mantle velocity structures and tectonic characteristics after one- and two-dimensional calculations and processing. The results show that the thickness of the crust and lithosphere gradually deepens from east to west along the profile. However, at the reflection/refraction interface, seismic waves in each group show obvious localized changes in each block. Also, the depth to the crystalline basement changes greatly, from as much as 7.8 km in the North China fault basin to only about 2 km beneath the Jiaodong Peninsula and Taihang-Lüliang area. The Moho morphology as a whole ranges from shallow in the east to deep in the west, with the deepest point in the Ordos Block at 47 km; in contrast, the North China Plain Block is uplifting. The L1 interface of the lithosphere is observed only to the west of Taihang Mountains, at a relatively slowly changing depth of about 80 km. The L2 interface varies from 75 to 160 km and shows a sharp deepening to the west of Taihang Mountains, forming a mutation belt.     

A modeling study on the controlling factors of seismic source distribution and their strength index——Practical analyses of the seismic environmental factors of the Honghe fault

IntroductionThe tectono-physical background and dynamic environmental features of strong earthquakes have long been studied from different viewpoints by seismologists both in domestic and abroad. Many controlling factors include the crust structure, lithological environment, tectonic conditions, the stress state, heat flow distribution and hydrodynamic effects at depth, etc. Some of the studies have established a foundation for researching and recognizing the spatial distribution of potential …     

Patterns of seismic sequences in the Levant—interpretation of historical seismicity

There are historical accounts of about a hundred damaging earthquakes that occurred during the last two millennia in the Levant, in and around the Dead Sea fault system, and about half of which were associated with additional felt shocks. Several modes of earthquake sequences can be distinguished in them: (a) In 46 accounts, only one single event is noted. These are not known from tectonic settings similar to that of the Levant, and may just be a result of incomplete reporting. (b) In four cases, quakes preceded the mainshock by minutes, hours, and up to several weeks—possibly foreshocks. (c) Thirty-five mainshock–aftershock sequences were noted, lasting hours, days, weeks, months, and even more than a year; four of these also have foreshocks. No typical delay time was recognized for the largest or most significant aftershocks: they appeared up to several months later. (d) Six of the reported mainshock–aftershock sequences appeared in a “storm.” Another 13 sequences are insufficient to specify further.     

Coherence of SH-waves near a semi-circular inclusion——the role of interference and standing waves

We present examples of a controlled numerical experiment that contribute towards understanding of the physical phenomena that lead to the reduction of coherency of strong earthquake ground motion. We show examples for separation distance of 100 m between the two points on the ground surface, which is in the range of engineering interest. Our examples illustrate the consequences of:(a) standing waves that result from interference of the incident and reflected waves from a near vertical contrast in material properties,(b) standing waves within a concave inhomogeneity(a semi-circular valley in our examples), and(c) smaller motions in the diffraction zone, behind the inhomogeneity. We show that it is possible to reduce coherency, to the extent observed for recorded strong earthquake ground motion, even by a single inclusion in a half space, for incident ground motion that is coherent. We also illustrate the combined effects of geometric spreading and finite fault width, superimposed on the otherwise dominating effects caused by interference. Our examples show reduction of coherence for specific angles of incident waves, while, for other angles of incidence, the coherence remains essentially equal to one.     

Research on the multifractal characteristics of the temporal—spatial distribution of earthquakes over New Zealand area

Using the Hill estimator,general multifractal characteristics of events in the New Zealand area have been dis-cussed.Results show that the spatial distribution of shallow events has apparent clustering characteristics,inde-pendent of the threshold magnitude;but for deep events these characteristics are not clear.While the time interval distribution has obvious clustering characteristics both for deep and shallow events,although with a different scal-ing range,the Hill estimates tend to indicate that the time interval distribution has a unifractal rather than a multi-fractal nature.All above reveal that the seismicity nature for shallow and deepevents is apparently different.     

Detection capabilities of the BURAR seismic array—contributions to the monitoring of regional and distant seismicity

Data recorded with the Bucovina Romanian Seismic Array (BURAR) seismic array between January 2005 and December 2008 were analyzed to verify the monitoring capabilities of regional and distant seismicity. For this time interval, nearly 35,000 events detected by BURAR and identified in seismic bulletins (Preliminary Determination of Epicenters and Romanian Earthquake Catalogue) were investigated using parameters as backazimuth, epicentral distance and magnitude. A remarkably detection capability is emphasized for teleseismic observations (Δ > 20°). BURAR onsets could be associated to almost 60% of all events in the teleseismic distance, with a magnitude detection threshold of 4.5 (mb). When no threshold magnitude is applied, the full detection capability of BURAR is in the same order as the performance of GERES array, which is one of the most sensitive stations in Central Europe. For regional events, detection capability decreases to about 16% of all events within regional distance range. The site conditions (crustal structure and high frequency cultural noise) as well as array dimension, affect the signal coherency and reduce the array detection capability for regional events. For both teleseismic and regional distances, a monthly variation of BURAR detection capabilities has been found; the number of events detected during the summer time is diminished by the specific seasonal human activity and atmospheric conditions (thunderstorms). To prove the good detection capability of the BURAR for teleseismic distances, a comparison with the observations of the Romanian Real Time Network in terms of magnitude and epicentral distance was carried out. The higher signal detection capability of BURAR is due to the array techniques applied in data processing, which enhance the signal-to-noise ratio. The monitoring performed by the BURAR seismic array provides a good azimuthal coverage of the regional and distant seismicity, in a large range of epicentral distances.     

On the chemical composition of atmospheric aerosols — Part I: Some stoichiometric aspects of the problem

Summary Following a recent hypothesis on the role of activated sodium chloride particles as possible condensation and sublimation nuclei, an analysis of data given byC. Junge on the chemical composition of aerosols, is made. It is established that all reported giant nuclei fall into three distinct categories of composition and that within each of these categories the ratio of the sums of anions to the sums of cations for constituents for which analyses were made, remains remarkably constant throughout the days of sampling, and for both geographic positions at which sampling has been carried out. A dependence of the hydroxide-carbonate content, on that of nitrate is also indicated in the «alkaline» nuclei. The system is treated as a saturated solution, and it is shown by the procedure of continuous variations that singularities occur at particular ratios of the prevalent chemical groups in solution, possibly indicating formation of complex species. This, together with the presence of double salts in the solid phase may be partly the reason for the constancy of ratio of sums in the groups of particles studied byJunge, while the grouping itself may depend on the origin and subsequent transformations of the particles.Parts of this paper were presented at the 174-th National Meeting of the American Meteorological Society, on the 29-th of January, 1959, in New York.     

The broad-spectrum adaptations of hominins in the later period of Late Pleistocene of China—Perspectives from the zooarchaeological studies

During the climatic fluctuations in the late Late Pleistocene, hominins in China had experienced some significant changes and adaptations in terms of subsistence strategies. Based on the zooarchaeological analyses of the faunal remains from the Shuidougou site of North China and the Ma'anshan site of South China, the present study demonstratively indicates that the broad-spectrum diet and its closely-related resource intensification for hominins were already at their places roughly at 33–35 cal ka BP. Compared to hominins of earlier period, who would have preferentially exploited large and medium-sized ungulates, hunter-gathers at later period had otherwise incorporated more small-sized animals(especially the quick ones, such as birds and hares) into their diet. Meanwhile, hominins of the later time had also greatly accelerated extractions and exploitations of the nutritional yields from the large and medium-sized animals. However, it seems clear from the current study that there was significant difference regarding the potential mechanisms for the broad-spectrum adaptations of hominins in the late Late Pleistocene of China.     

Parameters of the Magnetoactive Layer of the Lithosphere for the Siberian Platform—Transbaikalia Profile Based on WDMAM 2.0 Model Data

Geomagnetism and Aeronomy - The results of the determination of the depths to the centroid, the top and bottom boundaries of the magnetoactive layer along the meridional profile starting on the...     

Geochemistry of the subduction-related magmatic rocks in the Dahong Mountains, northern Hubei Province——Constraint on the existence and subduction of the eastern Mianle oceanic basin

Being a composite collisional orogen between North China and South China blocks, the Qinling orogenic belt is the key to understand the composite combination, prolonged evolutionary history and their continental dynamics. The main suture between north and south Qinling, called Shangdan suture zone (SDSZ), had been studied in detail for about twenty years. Recently, another suture zone, called Mianl黣 suture zone (MLSZ), has been identified in the Qinling Mountains. It is characterized b…     

Tidal friction — on the phase lag of body tides

Summary Oceanography, seismology, gravimetry, lunar laser ranging (LLR) and satellite observations yield various values of the amplitude of the phase lag of body (solid) tides. These results are discussed, the probable value of is lower than 0.3 deg, but a sufficiently accurate value is not yet known.Dedicated to the 75th Birthday of Professor Academician Tibor Kolbenheyer     

Emissions of antifouling-biocides into the North Sea —an estimation

Summary Ship owners coat the wetted surface of vessels with toxic paints to prevent fouling which increases fuel consumption. The active biocides in the paints are mainly TBT (tributyl tin), copper, and organonitrogen compounds. The amounts of biocides emitted by the German fleet and the world fleet are estimated, and the theoretical concentrations of biocides in the North Sea caused by shipping are valididated by measurements of other authors.

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Schätzung der Immissionen von Antifouling-Bioziden in die Nordsee

Zusammenfassung Die vom Seewasser benetzte Außenhaut von Schiffen wird mit giftigen Farben beschichtet. Damit verhindert man die Besiedelung durch Organismen, das fouling, das den Widerstand der Schiffe und damit den Brennstoffverbrauch steigert. Die aktiven Biozide der Farben bestehen hauptsächlich aus TBT (Tributyl-Zinn), Kupfer und Organo-Stickstoff-Verbindungen (S-Triazine). Für die deutsche Flotte und die Weltflotte werden Mengen der Biozide überschläglich berechnet. Außerdem wird die theoretische Konzentration der emitierten Biozide in der Nordsee vom Schiffsverkehr abgeleitet und mit Messungen anderer Autoren verglichen.

     

Conventional Oil—The Forgotten Part of the Water-Energy Nexus

The impacts of unconventional oil and gas production via high-volume hydraulic fracturing (HVHF) on water resources, such as water use, groundwater and surface water contamination, and disposal of produced waters, have received a great deal of attention over the past decade. Conventional oil and gas production (e.g., enhanced oil recovery [EOR]), which has been occurring for more than a century in some areas of North America, shares the same environmental concerns, but has received comparatively little attention. Here, we compare the amount of produced water versus saltwater disposal (SWD) and injection for EOR in several prolific hydrocarbon producing regions in the United States and Canada. The total volume of saline and fresh to brackish water injected into depleted oil fields and nonproductive formations is greater than the total volume of produced waters in most regions. The addition of fresh to brackish “makeup” water for EOR may account for the net gain of subsurface water. The total amount of water injected and produced for conventional oil and gas production is greater than that associated with HVHF and unconventional oil and gas production by well over a factor of 10. Reservoir pressure increases from EOR and SWD wells are low compared to injection of fluids for HVHF, however, the longer duration of injections could allow for greater solute transport distances and potential for contamination. Attention should be refocused from the subsurface environmental impacts of HVHF to the oil and gas industry as a whole.     

Floods at the northern foothills of the Tatra Mountains — A Polish-Swiss research project

The present paper introduces the topical area of the Polish-Swiss research project FLORIST (Flood risk on the northern foothills of the Tatra Mountains), informs on its objectives, and reports on initial results. The Tatra Mountains are the area of the highest precipitation in Poland and largely contribute to flood generation. The project is focused around four competence clusters: observation-based climatology, model-based climate change projections and impact assessment, dendrogeomorphology, and impact of large wood debris on fluvial processes. The knowledge generated in the FLORIST project is likely to have impact on understanding and interpretation of flood risk on the northern foothills of the Tatra Mountains, in the past, present, and future. It can help solving important practical problems related to flood risk reduction strategies and flood preparedness.